Definition: You are given a question on astronomy. Astronomy is a natural science that studies celestial objects and phenomena. You are also given 4 answer options (associated with "A", "B", "C", "D"), out of which only one is correct. You need to answer the question by selecting the correct option. You should only answer with the choice letter, not the whole answer.
Input: Calculate the ratio of the solar radiation flux on Mercury's surface for perihelion (0.304 AU) versus aphelion (0.456 AU).
(A)4:1 (B)1:2 (C)6:5 (D)9:4

D